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Les langues disponibles
Optics
Fibroptonic
Ref : 202 012
Alternative version: replace the spring with a vibrating wire which cuts the laser beam and
study the action of the tension of the wire on its period of vibration.
6 Experiment no. 21
Determining the period of a pendulum
ENGLISH
•
Depending on the relative position of the laser and the mass at rest, we observe
1 or 2 interruptions of the beam per period of the spring (refer to figures 17 and
18).
•
With this experiment we can study the influence of the mass attached to the
spring on the period. To study the influence of the spring constant, the spring
must be changed.
•
We can also intercept the laser beam by the turns; in this case it is necessary to
know the number of turns, which intercept the beam.
•
The pendulum consists of a small mass attached to a thread with a length of a
few centimetres.
•
In the set-up of figure 23, we replace the spring with the pendulum; the mass
when at rest intercepts the laser beam. Thus the signal detected by the
oscilloscope has 2 minima per period.
•
This experiment helps verify the relation between the period of a simple
pendulum and its length (T varies with L^½).
•
If the oscilloscope has a high-performance time base: 0.1 s/cm or even 0.5 s/cm
or 1 s/cm, it is possible to determine much longer periods and study all sorts of
pendulums.
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